C#-排序datagridview的麻烦 [英] C# - troubles with sorting datagridview
问题描述
我已经搜寻了我的问题的答案. 我已经开发了一个带有一些datagridviews的c#Winforms程序.
I have searched my ass off for the answer of my problem. I have developed a c# Winforms program with a few datagridviews.
问题是我希望成为能够通过单击列标题对datagridview进行排序的用户(我认为这将是标准的...) 但这是行不通的.
The problem is that I want to be the user able to sort the datagridview by clicking on the columnheader (i thought this would be standard...) But it is just not working.
我尝试了dgv.Sort方法,但这引发了一个例外,即datagridview必须绑定到IBindingList,但是我不知道如何执行此操作,我真的不想重新开发所有内容..
I tried the dgv.Sort-method but this throws an exception that the datagridview has to be bound to an IBindingList but I have no clue how to do that and I really do not want to redevelope everything..
这是我填充dgv的方式.
Here's how I populate my dgv.
我有一些自定义对象,并将它们放入列表中.此列表完全填充后,我将其设置为dgv的数据源.
I have certain custom objects and put them into a list. When this list is fullypopulated I set it as the datasource for the dgv.
list.Add(costumobject);
.
.
.
dgv.DataSource = list;
能否请您告诉我一种使排序功能正常工作的快捷方法?
Could you please tell me a quick way to make the sort-function working?
亲切的问候,
推荐答案
创建SortableBindingList而不是列表.
Create a SortableBindingList instead of a List.
using System;
using System.Collections.Generic;
using System.ComponentModel;
namespace YourNamespace
{
/// <summary>
/// Provides a generic collection that supports data binding and additionally supports sorting.
/// See http://msdn.microsoft.com/en-us/library/ms993236.aspx
/// If the elements are IComparable it uses that; otherwise compares the ToString()
/// </summary>
/// <typeparam name="T">The type of elements in the list.</typeparam>
public class SortableBindingList<T> : BindingList<T> where T : class
{
private bool _isSorted;
private ListSortDirection _sortDirection = ListSortDirection.Ascending;
private PropertyDescriptor _sortProperty;
/// <summary>
/// Initializes a new instance of the <see cref="SortableBindingList{T}"/> class.
/// </summary>
public SortableBindingList()
{
}
/// <summary>
/// Initializes a new instance of the <see cref="SortableBindingList{T}"/> class.
/// </summary>
/// <param name="list">An <see cref="T:System.Collections.Generic.IList`1" /> of items to be contained in the <see cref="T:System.ComponentModel.BindingList`1" />.</param>
public SortableBindingList(IList<T> list) : base(list)
{
}
/// <summary>
/// Gets a value indicating whether the list supports sorting.
/// </summary>
protected override bool SupportsSortingCore
{
get { return true; }
}
/// <summary>
/// Gets a value indicating whether the list is sorted.
/// </summary>
protected override bool IsSortedCore
{
get { return _isSorted; }
}
/// <summary>
/// Gets the direction the list is sorted.
/// </summary>
protected override ListSortDirection SortDirectionCore
{
get { return _sortDirection; }
}
/// <summary>
/// Gets the property descriptor that is used for sorting the list if sorting is implemented in a derived class; otherwise, returns null
/// </summary>
protected override PropertyDescriptor SortPropertyCore
{
get { return _sortProperty; }
}
/// <summary>
/// Removes any sort applied with ApplySortCore if sorting is implemented
/// </summary>
protected override void RemoveSortCore()
{
_sortDirection = ListSortDirection.Ascending;
_sortProperty = null;
_isSorted = false; //thanks Luca
}
/// <summary>
/// Sorts the items if overridden in a derived class
/// </summary>
/// <param name="prop"></param>
/// <param name="direction"></param>
protected override void ApplySortCore(PropertyDescriptor prop, ListSortDirection direction)
{
_sortProperty = prop;
_sortDirection = direction;
List<T> list = Items as List<T>;
if (list == null) return;
list.Sort(Compare);
_isSorted = true;
//fire an event that the list has been changed.
OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
}
private int Compare(T lhs, T rhs)
{
var result = OnComparison(lhs, rhs);
//invert if descending
if (_sortDirection == ListSortDirection.Descending)
result = -result;
return result;
}
private int OnComparison(T lhs, T rhs)
{
object lhsValue = lhs == null ? null : _sortProperty.GetValue(lhs);
object rhsValue = rhs == null ? null : _sortProperty.GetValue(rhs);
if (lhsValue == null)
{
return (rhsValue == null) ? 0 : -1; //nulls are equal
}
if (rhsValue == null)
{
return 1; //first has value, second doesn't
}
if (lhsValue is IComparable)
{
return ((IComparable)lhsValue).CompareTo(rhsValue);
}
if (lhsValue.Equals(rhsValue))
{
return 0; //both are the same
}
//not comparable, compare ToString
return lhsValue.ToString().CompareTo(rhsValue.ToString());
}
}
}
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